Lubricating oils containing benzalcyclohexylamine and bis-phenols



United States Patent 3,173,871 LUBRICATIN G OILS CONTAINING BENZALCY- CLOHEXYLAMINE AND BIS-PHENOLS John Scotchford Elliott, London, England, assignor to Castrol Limited, London, England, a British company No Drawing. Filed May 25, 1962, Ser. No. 197,571 Claims priority, application Great Britain, June 8, 1061, 20,819/61 9 Claims. (Cl. 252--51.5)

The invention relates to lubricating compositions and in particular to compositions based on mineral lubricating oils containing additives to impart oxidation resistance and anti-corrosion properties.

It is known that a lubricating or anti-corrosive composition may contain small proportions of a compound obtained by the action of an aldehyde or ketone on a non-aromatic basic water-soluble primary or secondary monoamine. The present invention relates to compositions containing specifically one such additive together with a certain class of antioxidants which have been found to be specifically suitable for use therewith.

According to the present invention, there is provided a lubricating composition comprising a major proportion of a mineral lubricating oil, from 0.3 to 2.0 percent by weight of (a) benzal cyclohexylamine and from 0.25 to 2.0 percent by weight of (b) an alkyl phenol having at least one secondary or tertiary alkyl substituent in the ortho position to the hydroxyl group.

The additive benzal cyclohexylamine appears to function in a lubricating composition not only as a corrosion inhibitor but also as a sludge dispersant; it may also be used with advantage in marine cylinder oils where, in some cases, this additive may be efiective as a dispersant and/or an inhibitor of varnish formation on pistons, as well as in some cases reducing cylinder liner wear.

The alkyl phenol of this invention may be represented by the general formula:

R4 TR]. R. t... it

where R is a branched chain alkyl group of 3 to 8 carbon atoms attached to the benzene nucleus at a carbon atom at which branching occurs; R R and R are hydrogen, or methyl groups or are the same as R and X is hydrogen, or is the same as R or is one of the following two groups:

Preferred compounds having the above general formula are those in which R; is the same as R i.e. is a branched tertiary alkyl group of 4 to 8 carbon atoms with no hydrogen atoms attached to the carbon atom adjacent to the benzene nucleus.

Specific examples of the alkyl phenol are as follows:

o-Isopropyl phenol 2,4 dimethyl-G-t-butyl phenol 2,6 di-t-butyl-4-methyl phenol 2,6 di-t-butyl phenol 1,1 bis(3,5 di-t-butyl-4-hydroxyphenyl)methane 3,3',5 ,5 tetra-t-butyl-4,4dihydroxydiphenyl 3-rnethyl 4,6 di-t-butyl phenol 4-methyl-2-t-butyl phenol Where the composition of the present invention is to be used in a marine crankcase or as a cylinder oil, it is preferred that additive (a) is present in the composition in amounts of from 0.5 to 1.0 percent by weight on the weight of the composition and that additive (b) is employed in amounts of from 0.3 to 1.0 percent by weight on the weight of the composition.

A preferred composition according to the invention comprises a major proportion of a mineral lubricating oil comprising 0.5 percent by weight of benzal cyclohexylamine and from 0.3 to 0.5 percent by weight of methylene bis (2,6 di-t-butyl phenol).

Following is a description by way of example of specific compositions in accordance with the present invention. Percentages are percentages by weight.

The examples of this invention are set forth in Table I and II together with comparative examples.

The utility of the present invention is demonstrated by means of the test data set forth in the following Tables I and II and the testing methods employed are as follows:

INSTITUTE OF PETROLEUM STANDARD METH- OD 114/56 T (MODIFIED) INSTITUTE OF PETROLEUM STANDARD METH- OD 19/ 61 DEMULSIFICATION NO.

20 ml. of the oil is emulsified with steam at about C. The emulsion is then placed in a bath at about 94 C. and the time for 20 ml. of oil to separate is recorded.

INSTITUTE OF PETROLEUM STANDARD METHOD 177/62 T TOTAL ACID NUMBER The sample of oil is dissolved in a mixture of toluene and isopropyl alcohol containing water, and is titrated potentiometrically with alcoholic potash to pH 11.

Mineral oil A is a blend consisting of 88% of a solvent refined mineral oil of viscosity about 145 seconds Redwood I at F. with 12% of a solvent refined brightstock of viscosity about 600 seconds Redwood I at 140 F.

The test data demonstrate that a lubricating composition suitable for lubricating marine crankcases which is based upon a mineral lubricating oil and contains benzal cyclohexylarnine is improved by the conjoint use therewith of antioxidants consisting of certain phenolic materials. Table I demonstrates that, as assessed by the total acid number and the demulsification value, a synergistic effect exists in those blends containing between 0.25 percent and 2.0 percent of the phenolic material in conjunction with between 0.3 percent and 2.0 percent of benzal cyclohexylamine. Further Table II demonstrates that a synergistic effect is present in the compositions containing benzal cyclohexylamine and mono or binuclear phenols.

T able 1 MODIFIED IP 114/56'1 OXIDATION TEST300 HOURS AT 110 C.-MINERAL OIL A Additives Present Tests on oxidised oils (Percent) Blend N0.

Methylene Benzal Acidity bis (2,6 di-tcyclohexyl- (TAN) Demuls. butyl phenol) amine Nil 0. 5 1. 39 1,200+ Nil 1. 3. 0 1 200+ 0. 2 0. 5 0. 24 1 200+ 0.25 0.25 1. 12 1 200+ 0. 25 0. 5 0. 08 780 0. 3 Nil 0. 73 1 200+ 0.3 0. l 0. 89 1, 200+ 0. 3 0. 2 0. 07 1, 200+ 0. 3 0. 5 0. 39 750, 630 0. 3 0.7 0, 34 600 0. 5 Nil 0. 86 1, 200+ 0. 5 0. 3 0. 13 540 0. 5 0. 5 0. 39 600 1. 0 Nil 0. 45 1, 200+ 1. 0 0. 5 0. 17 840 2. 0 1. 0 0. 1, 200+ Table II MODIFIED IP 114/56'1 OXIDATION TEST-300 HOURS AT 110 C.-MINERAL OIL A I claim:

1. A lubricating composition comprising a major proportion of a mineral lubricating oil, from 0.3 to 2.0 percent by weight of (a) benzal cyclohexylamine and from 0.25 to 2.0 percent by weight of (b) an alkyl phenol having the following formula:

where R is a tertiary butyl group; R is selected from the group consisting of methyl and tertiary butyl groups, and

'1: X is selected from the group consisting of methyl, tertiary butyl and and where R and R are as defined above.

2. A composition as claimed in claim 1 wherein the alkyl phenol is 4,4 methylene bis(2,6 di-t-butyl phenol).

3. A composition as claimed in claim 1 wherein the alkyl phenol is 2,6 di-t-butyl-4-methyl phenol 4. A composition as claimed in claim 1 wherein the alkyl phenol is 12,6 di-t-butyl phenol.

5. A composition as claimed in claim 1 wherein the alkyl phenol is 4,4 bis(2,6-cli-t-butyl phenol).

6. A composition as claimed in claim 1 wherein the alkyl phenol is 2,4 dimethyl 6t-butyl phenol.

7. A composition as claimed in claim 1 wherein there is present from 0.5 to 1.0 percent by weight of benzal cyclohexylamine.

8. A composition as claimed in claim 1 wherein there is present from 0.3 to 1.0 percent by weight of the alkyl phenol.

9. A lubricating composition comprising a major proportion of a mineral lubricating oil about 0.5 percent by weight of benzal cyclohexylamine and from 0.3 to 0.5 percent by weight of methylene bis (2,6 di-t-butyl phenol).

References Cited by the Examiner UNITED STATES PATENTS 2,060,138 11/36 Taylor 252-390 X 2,225,533 12/40 Dewey 252-515 2,303,819 12/42 Cantrell et a1. 44-73 2,308,282 l/43 Howland et al 252-390 X 2,809,164 10/57 Pruett 252-404 X 2,900,417 8/59 Filbey et al. 252-52 X 2,923,745 2/60 Buls et al. 252-404 X 2,944,086 7/60 Cofiield et a1. 252-404 X 3,032,502 5/62 Barnes 252-515 3,043,775 7/62 Coflield et a1. 252-52 FOREIGN PATENTS 618,083 2/ 49 Great Britain.

OTHER REFERENCES Morawetz: Phenolic Antioxidants for Parafiinic Materials, I and E Chem., 41, 1441-1447 (July 1949).

DANIEL E. WYMAN, Primary Examiner.

JULIUS GREENWALD, Examiner. 

1. A LUBRICATING COMPOSITION COMPRISING A MAJOR PROPORTION OF A MINERAL LUBRICATING OIL, FROM 0.3 TO 2.0 PERCENT BY WEIGHT OF (A) BENZAL CYCLOHEXYLAMINE AND FROM 0.25 TO 2.0 PERCENT BY WEIGHT OF (B) AN ALKYL PHENOL HAVING THE FOLLOWING FORMULA: 